This invention relates to the production of arylene sulfide polymers with reduced melt crystallization temperatures.
Arylene sulfide polymers are known in the art and useful in a variety of applications, which include films, fibers and molded articles.
Melt crystallization temperature (T.sub.mc) is an important characteristic in the determination of the final use of arylene sulfide polymers. The melt crystallization temperature (T.sub.mc) indicates the temperature at which the polymer begins to crystallize when cooled from the melt. In the production of arylene sulfide polymer films, for example, biaxially oriented thick film, the cast film should be amorphous (non-crystalline) before stretching. Arylene sulfide polymers are generally crystalline in that they exhibit a temperature of melt crystallization (T.sub.mc) when cooled from a melt. In current preparation methods, quenching is used to prevent crystallization of poly(arylene sulfide) cast film. This amorphous film is reheated to a working temperature prior to stretching.
Quenching of a conventional poly(arylene sulfide) cast film to prevent crystallization is less effective as film thickness increases. Conventional poly(arylene sulfide) cast film has a relatively high T.sub.mc (about 180.degree.-220.degree. C.) and therefore crystallizes easily during cooling. The center of a thick film is insulated and is less affected by quenching so, therefore, the center of a quenched thick film of high T.sub.mc is crystalline. It is therefore desirable, for film applications, preferably for the formation of thick films, to provide an arylene sulfide polymer which has a relatively low T.sub.mc. A poly(arylene sulfide) filme of relatively low T.sub.mc would be amorphous even at slow quench rates, and a poly(arylene sulfide) thick film of relatively low T.sub.mc would be amorphous at conventional quench rates. In order to obtain a thick film, therefore, it is necessary to maintain a low T.sub.mc during film preparation.
It is known to use various processing methods to affect the T.sub.mc of the arylene sulfide polymer. However, the use of these methods leads to increased time and energy cost in processing the arylene sulfide polymer. Thus the need for an effective method of lowering the T.sub.mc of the arylene sulfide polymer still exists.
It is therefore an object of my invention to provide a method of reducing the melt crystallization temperature of an arylene sulfide polymer.
It is also an object of my invention to provide an arylene sulfide polymer which exhibits a lower melt crystallization temperature.